Evaluation On Photosynthesis Efficiency And Their Responses To Drought Stress Of The Alien Wheat Germplasm

Wheat?Triticum aestivum L.?is one of the important crops in the world,with the population growing,the scarcity of water resources and the cultivated land is shrinking.Wheat production is faced with severe situation.Long time of the artificial selective breeding which makes the genetic basis of wheat has become increasingly narrow,and thus difficult to deal with a variety of biotic and abiotic stress.The use of distant hybridization and chromosome engineering has created different additional materials including wheat additions,triticale and synthetic wheat.To application of the benefit traits of wheat germplasm in breeding,it's reasonable to evaluation of there genetic effect,photosynthetic potential and drought resistance.In order to evaluation the properties and potential utilization of the common used wheat germplasm materials,including wheat addition lines?CA?,hexaploid Triticale?HT?,octoploid Triticale?OT?and synthetic hexaploid wheat lines?SHW?,the agronomic traits,photosynthetic characteristics,fluorescence parameters under drought stress were investigated.And analyzed the drought resistance and antioxidant enzyme activity among the SHWs.The main results were as follows:1 Evaluation on the agronomic traits and photosynthetic traits of different wheat germplasm materialsThe photosynthetic capability of wheat germplasm with different alien chromosomes were investigated and compared with bread wheat cultivars?BC?in this study,including wheat addition lines?CA?,hexaploid Triticale?HT?,octoploid Triticale?OT?,and synthetic hexaploid wheat lines?SHW?.Result indicated that HT,OT and SHW produced significantly lengher spike and higher biomass plant^-1?BMPP?.HT and OT showed excellence traits on spike number?SN?and grain number per spike?GNPS?.While,SHW displayed lower production on GNPS and grain yield.Distinct superiority of net photosynthetic rate?Pn?and carboxylation activities of ribulose-1,5-bisphosphate carboxylase/oxygenase?rubisco?was observed in HT and OT.Meanwhile,OT showed the highest expression of rubisco large subunit gene?rbcL?in the flag leaves at heading and grain-filling stages,though the coding region of rbcL was highly conserved in all investigated materials.Further analysis indicated that OT and CA displayed higher expression of rubisco small subunit gene?rbcS?.Correlation analysis revealed that there were significant and positive correlations between Pn with the expressions of rbcL?at both heading and grain-filling stages?,the expression of rbcS?at heading stage?,and the carboxylation activity of rubisco?at grain-filling stage?.Anatomical structure analysis of chloroplast observed longer chloroplast,more chloroplast grana and grana lamella in SHW.In conclusion,HT and OT with rye chromosomes displayed greater photosynthetic capability,and could be applied in improving photosynthesis efficiency and physiology breeding programs.2 Character of photosynthetic index,stomata characteristics and Chlorophyll fluorescence parameters in different wheat germplasm under different water conditionsDifferent types of germplasm resources,including common wheat,hexaploid triticale,octoploid triticale and synthetic wheat were investigated on the agronomic traits and photosynthetic fluorescence parameters in two water regimes,i.e,well watered?WW?and water stressed?WS?.Under the condition of water stress,three periods of flag leaf net photosynthetic rate,chlorophyll content and maximum PS?photochemical quantum efficiency?Fv/Fm?were significantly decreased?P<0.01?,and stomatal limitation?Ls?increased significantly.The actual photochemical quantum efficiency of PS???PS??and coefficient of photochemical quenching?qP?at flowering stage and grain-filling stage were also decreased.Based on drought-resistant coefficient of biomass and yield index,certa was identified with higher drought resistance.All materials were divided in to two groups?higher and lower?based on the yield drought-resistant coefficient.Under the drought conditions,higher drought resistance group is significantly higher than low resistance group for net photosynthetic rate,?PS?and qP at flowering and grain-filling stage.Low resistance groups with significant higher stomatal limitation than higher drought resistance group at heading,flowering and grain-filling stage.No significant difference were observed between the two groups for Fv/Fm.The lower drought resistance group displayed significant lower chlorophyll content than the higher drought resistance group at the three investigated stage.Correlation analysis showed that,under the irrigation conditions,the yield showed significant correlation with net photosynthetic rate and relative chlorophyll content at heading,flowering and grain-filling stage,displayed significantly negative correlation with Ls at the flowering and grain-filling stage.Meanwhile,significantly positive correlation between yield with Fv'/Fm',and significantly negative correlation between yield with qN at the flowering and grain-filling stage were also observed.Under drought stress conditions,the yield showed significant positive correlation with the net photosynthetic rates at the flowering and grain-filling stage,and displayed a significant positive correlation with the relative chlorophyll content and a significant negative correlation with Ls at the three stages.Besids,the three stages of Ls have reached the significant level of negative correlation with yield.3 Evalution on the genetic diversity,agronomic traits and garin quality of synthetic hexapoid wheatIn order to promote the utilization of SHWs in wheat breeding,Comprehensive appraisal of 34 SHWs derived from different Ae.tauschii accessions with common wheat in genetic diversity,root characters,photosynthesis characteristic,yield Components agronomic traits and grain quality.Some SHW individuals with outstanding agronomic and physiological traits were qualified in two years.The results showed that lower genetic similarity coefficient existed between SHWs and common wheat?0.39?.At the seedling stage,SHW material were more inclined to increase the single length of the root,nine of SHW materials?26.47%?were significantly longer than common wheat cultivar Jinmai47 for coleoptile length.SHW materials showed negative character for the root surface area and root volume,while 58.82%of SHWs displayed positive character on root diameter.Difference with common wheat Jinmai47,the SHW material were more inclined to increase the single length of the root,most of the SHW material have three root division,less than Jinmai47.Most of SHW lines showed no significance difference with Jinmai47 for the photosynthetic traits and SPAD?P<0.05?.And the number of SHW lines which present higher WUE than Jinmai47 were rising with the stage development in both two years.Some of the prominent agronomic traits were identified in considerable SHW lines,such as larger leaf area,lengthy spike length,more tiller and high-producing Biomass.SHW lines displayed significant lower harvest index than Jinmai47.In the aspect of grain quality,thirty-three of SHW lines?97.06%?were significantly length than Jinmai47 for the grain length.The SHW materials content significantly more fibre?thirty-four lines,100%?,gluten and protein than Jinmai47,All SHW lines were significant harder than Jinmai47 and significantly lower than Jinmai47 for the starch content.Some unfavorable traits of SHW lines also have been identified when compared with Jinmai47,include higher PH,less GNPS and lower HI.4 Drought resistance of new synthetic hexaploid wheat accessions evaluated by multiple traits and the activities of antioxidative enzymesThe drought resistance of thirty-four new SHWs along with the control?bread wheat cultivar Jinmai47?were evaluated under two water regimes,i.e,well watered?WW?and water stressed?WS?in two consecutive years.The membership function value of drought resistance?MFVD?analysis based on FLA,tiller number?TN?,BMPP and GYPP and drought resistance index?DI?based on BMPP and GYPP under two water regimes identified six SHW lines?SHW1,SHW3,SHW10,SHW16,SHW21,SHW34?with higher drought resistance.When challenged by drought stress,the activities of antioxidant enzymes,including superoxide dismutase?SOD?,peroxidase?POX?and catalase?CAT?were higher in WS plot than in WW plot.SHWs with higher drought resistance exhibited higher activities of antioxidant enzymes?SOD,POX and CAT?in both WW and WS plots.SHWs with excellent agronomic traits and higher drought resistance identified in this study could be further applied in stress resistance studies and wheat breeding programs.